Add support for emissive and gloss-maps

Conflicts:
	code/ObjFileMtlImporter.cpp
	Someone added support for loading more bump maps, I added support for emmissive-maps. Easy merge.
Fixes warnings in clang for unrecognized attribute 'gcc_struct'
Merge pull request #208 from NickNick/master

Add support for emissive and gloss-maps